Smoked SST-90

lightliker

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After reading many posts of self builters I thought: "well, why not take a chance!" and ordered a SSR-90 at AMU-electronics in Germany. The package came in within a week after ordering :thumbsup:

When measuring it with my Fluke79, I didn't got a reading (resistance infinately) nor saw the LED glowing up, a bit strange because the at the same time arrived XM-L leds did glow up a bit when measured by the Fluke79.:candle:
Since I red that the SST-90 needs about one amp to start up, I ignored this fact and started soldering wires at the star board.

One of the four connections I didn't like so I desoldered two of them and went on with screwing the star on a CPU couler with a therman capacity of at leat 50 Watts.


Since the powerbuck driver (ordered previous week at cpf) should have landed at my front door, I used a 700 mA driver in order to start really slowly on this baby.
Nothing happened so I tried the 3A conlux driver, ordered at dotlight.de

Guess what: nothing happened too...


Now I started trembling and decided to measure the LED.
My nightmare came true: 0,6 ohm, the resistance of the wires of my Fluke 79!! :ohgeez:
I desoldered all the wires, hoping taht I might have soldered a shortcut but nothing helped at all.:sigh:
Tis morning I had some more daylight and made a macro-picture.

This doesn't look nice at all.:fail:

The poor LED did not lit up a micro second :mad: and I took as many precousions to solder the SST-90 as quick as possible, using a weller soldering station and cooling it down right after soldering it.

Has anybody ever seen a tiny black dot in one of the lines within the yellow led-field when looking at a defective SST-90?
Could anybody take a multimeter and measure the resistance for me (my fluke79 has a special diode measuring level) to look if it glows up a bit??
Could this be a faulty LED or did I kill it while soldering it?? :eek:

I soldered the XM-L at exactly the same way and this baby really lights u a hole room at 8 meters distance using it's own 100 or 120 degrees lense!

Any suggestions would be really appreciated!!
 
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lightliker

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from what you're writing, it seems the SST90 never was working at all!

Craig

Thanks Craig, hopefully does AMU-electronics share your opinion!!
When this baby's die on me as quick as this one did, I don't know If I have the funds to get my first flashlight even starting...
 

moderator007

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Did you reflow the led on the pcb or did it come soldered already. Sometimes if the solder is not making good contact between the led and pcb, the led will work but seems like its dying then sometimes stops working altogether. Sometimes it never lights up at all. The bad connection gives out under the current. If you have the led off the pcb, you could connect your driver up to the bottom solder pads on the led and see if it works then. Its possible it needs to be reflowed on the pcb. It also could be possible the led is mounted backwards on the pcb, wrong polarity.
If it doesnt work by give it power directly to the led bottom solder pads then more than likely it is bad.
 
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lightliker

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Did you reflow the led on the pcb or did it come soldered already. Sometimes if the solder is not making good contact between the led and pcb, the led will work but seems like its dying then sometimes stops working altogether. Sometimes the never light up at all. The bad connection gives out under the current. If you have the led off the pcb, you could connect your driver up to the bottom solder pads on the led and see if it works then. Its possible it needs to be reflowed on the pcb. It also could be possible the led is mounted backwards on the pcb, wrong polarity.
If it doesnt work by give it power directly to the led bottom solder pads then more than likely it is bad.

The connection is short-cirquited to 0,7 ohm so any attampt of a driver will result in switching to safety-cut-off.
I try to get some pictures on a website in order to let you see what I mean.
If AMU-electronics has problems with delivering another LED, how can I desolder the LED, that is already delivered on a Star board (original luminus)?
Is the LED glued onto the board or can I just put it on an aluminium plate that is brought to a temperature of about 190 degrees celcius and take off te SST-90?
Still I think the SST-90 is gone because of the dark spot at une of the rows...
pouvre pouvre LED.......
 

moderator007

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If AMU-electronics has problems with delivering another LED, how can I desolder the LED, that is already delivered on a Star board (original luminus)?
Is the LED glued onto the board or can I just put it on an aluminium plate that is brought to a temperature of about 190 degrees celcius and take off te SST-90?
Still I think the SST-90 is gone because of the dark spot at une of the rows...
pouvre pouvre LED.......
You have the general idea. I usually just use a 150 watt solder iron under the aluminum pcb While pushing slightly with a small flat screwdriver, heating it up slowly until it slides off. I hold the pcb with the helping hands. Here's a good link on the reflow process.
A few other methods in this thread here. This is what the manufacturer recommends.
I think you might be right about the dark spot. Looks like that this led would have been tested in some point in time before you received it.
 
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lightliker

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A few days ago I contacted AMU-electronics and they promised me to send a replacement LED :twothumbs:twothumbs
Way to go AMU-electronics!!!

Now it is waiting for my BuckConverter from Der Wichtel.
It arrived a week ago, what a piece of art work!! :D

http://i1178.photobucket.com/albums/x368/lightliker/SST-90 adventure/IMG_2103.jpg

Strange enough there were no leads for the potentiometer so I mailed Yitao.
He was glad to know where the other mixed up driver went to and will send me the right one this weekend.:whistle:

This gives me the time to think about how solder a LED even faster and look out for some reflectors this coming week.....

I'll be back :poof:

Edit: On special request I placed a less "nude"picture of this nice driver :)
 
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lightliker

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You have the general idea. I usually just use a 150 watt solder iron under the aluminum pcb While pushing slightly with a small flat screwdriver, heating it up slowly until it slides off. I hold the pcb with the helping hands. Here's a good link on the reflow process.
A few other methods in this thread here. This is what the manufacturer recommends.
I think you might be right about the dark spot. Looks like that this led would have been tested in some point in time before you received it.

Thanks very much moderator007
Before even soldering it I will clamp the new LED with some springs and cooling paste to the cooling body and connect it with to needles, pressing at the contacts (the same way the test the LEDs in the factory I think.

Now I have to find some nice reflectors with the accent on flood but with enough throw. D.E. has a nice one for less than 10 bucks.
Any suggestion is welcome!!
 

ExtremeX

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That sucks, sounds like the vendor is taking care of you.

I killed an XM-L led just playing around wth a bench power supply / not paying attention to the voltage. Sucks, since I JUST got it after a long wait from china just to kill it right away :oops:
 

jasonck08

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That sucks, sounds like the vendor is taking care of you.

I killed an XM-L led just playing around wth a bench power supply / not paying attention to the voltage. Sucks, since I JUST got it after a long wait from china just to kill it right away :oops:

haha I did that to an XM-L too. Upped the voltage too fast and the current spiked to 10A for a second and :poof:
 

lightliker

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There is a way to give life to your LED again. Zapping...

What do you mean??
I sent the led back to AMU but still haven't received the replacement yet........
This weekend won't be much time so this is gonna be a long story....
 

bshanahan14rulz

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sometimes LEDs can be brought back to life by applying a relatively high reverse voltage across the electrodes.

edit: csshih says forward voltage, and I trust him more than my memory.
 
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Mike S

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sometimes LEDs can be brought back to life by applying a relatively high reverse voltage across the electrodes.

Is there a thread on how to do this? I killed one SSR-90 by connecting the positive and negative wires to both positive pads on the star and also killed an XR-E by powering it up with the source set to 12V. It sounds like it's worth a shot.
 

csshih

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sometimes LEDs can be brought back to life by applying a relatively high reverse voltage across the electrodes.

well no, that's only if the die produces a conduction channel, from what I've read. I think this case either there's something more serious wrong with the die, as there's a black spot! Honestly it looks like someone had previously pumped quite a few too many amps through it as the phopshor on the left and right appear to be creeping away from the bond wires, and it looks like the bond wire detached on the upper right corner.

Is there a thread on how to do this? I killed one SSR-90 by connecting the positive and negative wires to both positive pads on the star and also killed an XR-E by powering it up with the source set to 12V. It sounds like it's worth a shot.

reverse the polarity and try to shove a few amps though it. I'm fairly sure your bond wires are disconnected, though.

-Craig

edit: oops, actually, try keeping the polarity normal.
 
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moderator007

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Honestly it looks like someone had previously pumped quite a few too many amps through it as the phopshor on the left and right appear to be creeping away from the bond wires, and it looks like the bond wire detached on the upper right corner.
I didn't notice that when I first looked at the pic. Yes, I agree csshih. It does look like it has been over driven or improper heatsinked.
 

Mike S

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reverse the polarity and try to shove a few amps though it. I'm fairly sure your bond wires are disconnected, though.

-Craig

edit: oops, actually, try keeping the polarity normal.

Thanks, I'll give it a try. When the SST-90 died, I did see some of the bond wires glowing right where they connect to the die.
 

lightliker

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Is there a thread on how to do this? I killed one SSR-90 by connecting the positive and negative wires to both positive pads on the star and also killed an XR-E by powering it up with the source set to 12V. It sounds like it's worth a shot.
With a bit of luck you could desolder the LED from it's star board (if you ordered this type) and use it with a special heatsink that is offered by one of the cpf members...
Did you measure thi pouvre pouvre LED??
I would think that only the printed connection would have been damaged by the high shortcirquit current....
 

lightliker

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Is there a member that could measure a SST-90 LED with a multimeter (i.e. fluke at diode measuring position)??
Since the LED hasn't arrived yet, I am very anxious to know what happens when measuring the SST-90

a) nothing at all :shakehead
b) a nice glow of the die :naughty:
c) :poof:
 
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